In medical devices for extracorporeal blood treatment (dialysis) frequently tube roller pumps are used for feeding the collected blood of the patient to a dialyser and back to the patient. Said tube roller pumps function as peristaltic pumps, wherein a loop-shaped tubing segment is adjacent to an appropriately bent bearing surface of the pump housing. A rotor of the pump located inside the bearing surface then moves with its outer edges along the tubing segment, wherein it locally impresses the tube and thus enables feeding of blood through the tubing segment by the elastic material properties of the tubing segment. For this purpose, the blood is fed to the tubing segment via a first port and is discharged again via another port at the other end of the tubing segment.
The tubing segment thus forms a transfer system, as it is called, e.g. together with the feeding and discharging lines and several air traps, by which transfer system the blood of the patient is fed to a dialyser and back to the patient. Those transfer systems are preferably exchanged after each treatment and are not re-used for other patients. A used tubing segment thus has to be removed from the pump before a new transfer system is introduced into the device. For facilitating the handling during removal and rigging of the transfer system it is further known to provide a connector adapted to be connected to a feeding and discharging line, respectively, at each of the two ends of the tubing segment.
For accommodating a tube inside a roller pump the U.S. Pat. No. 8,047,819 B2, for example, describes holding means that are detachably mounted on the pump housing. So for different sizes and types of tubes different holding means can be mounted on the pump. A holding means includes a clamping device including at least one pivoting clamp jaw having a semicircular recess so that a tube can be held in said semicircular recess and an opposed equally semicircular recess of another clamp jaw. The clamp jaws can also include plural of said recesses so that plural tubes can be simultaneously accommodated.
Moreover automatic systems are known that are intended to take over and thus facilitate threading and unthreading of the tube into the pump. Frequently, for unthreading an actuator moving the system from its therapy position into an unthreading position via a linear drive, for instance, has to be operated. For this purpose, it can be required in those systems to operate a switch/button at the medical device or to touch a software button on user interface.
Furthermore, multi-connectors are known which combine both terminals for feeding and discharging lines in one component part which then can be introduced into a receiving portion of the pump housing. Via the geometric shape of such multi-connectors it is possible to detect the presence thereof in the pump by the fact that during the inserting operation for instance a cylindrical portion of the multi-connector operates a plunger the axial position of which is queried via a light barrier. At the same time this plunger is part of an electromechanical actuator mounted in the pump housing which is adapted to eject the multi-connector via a linear drive.
In order to move a tubing segment at a tube roller pump into the respective threading and unthreading position, e.g. from JP 2008-000425 several variants of a pivoting member or rocker arm are known to which both ends of the loop-shaped tubing segment can be fastened. In a first pivoting position of the rocker arm the tubing segment then is provided in a position in which the threading operation can be started while the tubing segment can be unthreaded in a different pivoting position. The automatic threading and unthreading operation is performed by guide pins at the periphery of the rotor, the guide pins pressing the tube into the pump housing or out of the latter upon rotation of the rotor.
Both ends of the loop-shaped tubing segment are lifted and lowered, respectively, by the rocker arm so that the guide pins have to be appropriately shaped so as to be capable of catching the tube in said two positions and pressing it into a particular direction. The automatic threading and unthreading operation must be adapted to be reliably implemented, but the tube must not be deformed too strongly.